The graph above displays the amount of caught cod (a type of fish) in the Atlantic. What is the best explanation for the change in the graph in the 1970s?
The number of cod caught after 1970 increased because cod were able to reproduce.
The number of cod caught after 1970 decreased because fishermen lost their boats in storms.
The number of cod caught after 1970 increased because of an increase in the number of fishermen.
The number of cod caught after 1970 decreased because of overfishing.